The ensiling process is a method of moist forage preservation and is used worldwide. Silage accounts for more than 200 million tons of dry matter stored annually in Western Europe and the United States alone. The process involves natural fermentation, where lactic acid bacteria ferment water soluble carbohydrates to form organic acids under anaerobic conditions. This causes a decrease in pH which then inhibits detrimental microbes so that the moist forage is preserved.
Aerobic instability is the primary problem in silage production. Traditionally, the recommendation has been to allow silage to ferment for at least thirty (30) days before feeding to aid in increased silage digestibility. Even before storage units are open for feedout, silage can be exposed to oxygen because of management problems (i.e., poor packing or sealing). Under these types of aerobic conditions, rapid growth of yeast and mold cause silages to heat and spoil, decreasing its nutritional value. Feeding a crop that has not been properly fermented can lower dry matter intake (DMI), decrease milk production, and cause digestive upsets. Allowing time for adequate fermentation creates a more palatable and digestible feed for optimum DMI and milk production.
Aerobic instability can be a problem even in inoculated silage that has undergone what would traditionally be considered a “good” fermentation: a rapid pH drop, and a low terminal pH. The yeast organisms which contribute to instability in these conditions however may be those which are tolerant of acid conditions and can metabolize the lactic acid produced by lactic acid bacteria during fermentation.
It is possible to use both chemical and biological additives in making silage to promote adequate fermentation patterns especially under sub-optimal conditions. Typical chemical additives are most often organic acids and biological additives comprise bacterial inoculants and enzymes. Bacterial inoculants have advantages over chemical additives because they are safe, easy to use, non-corrosive to farm machinery, they do not pollute the environment and are regarded as natural products.
Production of silage inoculant strains and the ensiling process is complex and involves interactions of numerous chemical and microbiological processes. Different strains of even the same species do not have identical properties and vary in their fermentation and production characteristics. Further, different silages and different methods of ensiling present a variety of different needs. A continuing need exists in the art for improved compositions and methods to improve the aerobic stability of silage and increase the efficient production of ensiled animal feed.
The present invention provides novel strains of L. buchneri and L. brevis and superior combinations thereof for use as silage inoculants.